The serial number plate appears to be original. The engine block stamp appears to be original. The certification team evidently felt the same way when the car was certified. You can get a copy of the certification paperwork from Jim O’Brien (PA) , who is the certification chair. Or the owner may have a copy.
You are doing your homework! That is a good thing when purchasing a car.

Don't rely on sellers claims. Bring a magnet. I don't know this car, just a tip on any purchase. If you are not going to inspect the car personally get some one to do it for you. I hope you are dealing with the owner and not a broker.
CORDiallyMike